Art of cutting circular and other nonrectangular blanks from sheet metal



I 1935- .s. H. MURCH 1,818,150

ART QF CUTTING CIRCULAR AND OTHER NONRECTANGULAR BLANKS FROM SHEET METAL1 Filed June 16 1924 2 Sheets-Sheet 1 ATTORNEY J. H. MuRcB 1,818,150

CTAHGULAR ART OE CUTTING CIRCULAR AND OTHER NONRE BLANKS FROK SHEETMETAL '-F'iled June 16, 1924 2 Sheets-Sheet 2 Z... lvI-lllrllll l 11VENTOR. 1% %7 A TTORNE Y Patented Aug. 11, 1931 UNITED STATES- JTOHN H.BURCH, OF EAST ORANGE, NEW JERSEY, ASSIGNOR TO AMERICAN CAN COM- PATENT;OFFICE PANY, OF NEW YORK, N. Y., A. CORPORATION OF NEW JERSEY ART OFCUTTING CIRCULAR AND OTHER NONRECTANGULAR BLANKS FROM SHEET METALApplication filed June 16,

This invention relates to formin of circular and other non-rectangularob ects from A prlncipal ob ect of the present invention is theprovision of a method of formin the can ends or other objects which wille ect a substantial saving of the sheet material.

In the cutting of round, oval and other duplicate articles from sheetmetal such as can ends, etc., the sheet is first cut into strips andthese strips fed through a strip feed ress to cut the blanks of thearticles and orm them. In order that wastage may be reduced to aminimum, these strips are cut by what is known in the industry asstaggered row layout. In accordance with this layout the outlines of thearticles to be cut, usually of circular form, are arranged in rowsacross the sheet, the members in each row being stag-- gered withrespect to the members of the rows lmmediately above and beneath, sothat across the sheet the top and bottom of one outline extends intoward the space between the adjacent outlines of the immediatelyadjacent rows. When the strips are cut, a cut is made along a scroll orundulating line which provides enlarged portions in each row from whichthe articles are to be cut. Because of these undulations and the varyingwidths, accurate arrangement and feeding of the strips in the strip feedpress is necessary. In the past it was required that each sheet betrimmed at its ends to provide accurate reference edges for the pressfeed members to engage in correct relationship with the dies. Thistrimming of the edges has resulted in an average wastage of one-eighthinch on each side of the sheet or a total wastage of the equivalent ofone-fourth inch wide and having a length the width of the sheet. In thecan makin industry the number of articles made is, 0 course, enormousand this wastage on this account is an item of real magnitude.

My invention contemplates the provision for accurate edge reference andengagement 1924. Serial No. 720,248.

without requiring the trimming of the sheet or wastage above mentioned.

Numerous other objects and advantages of the invention will be apparentas it is better understood from the following description, which, takenin connection with the accomanying drawings, discloses afpreferredemodiment thereof.

Referring to the drawings,

Figure 1 is a side elevation, partially in section, of a shearingmachine;

Fig. 1 is an end elevation of a strip feed press;

Fig. 2 is an enlarged partial plan section on the line 2-2 of Fig. 1; vr

Fig. 3 is an enlarged detail of the strip feed press; and

Figs. 4 and 5 are fragmentary views illustrating the staggered layoutand the cutting of the sheet in accordance with my improved method offeed press.

In accordance with the staggered layout the'sheet of tin plate or othermaterial is cut into strips along lines 11 and 12, said lines 11 and 12being broken or of scroll character to accommodate lines of die action13, enlargements, as shown, being alternately positioned in adjacentrows across the sheet.

Prior to my invention it has been necessary to trim along the line 14:at each side of the sheet to remove the strip 15 of a proximatelyone-eighth inch width and in the use of my present invention thistrimming is not performed and more of the sheet is preserved for usefulcutting. The staggered arrangement provides for the cuts extendingnearly to the edge of the sheet on each side in alternate rows (see topand bottom rows in Figs. 4 and 5). There must or should be left aboutone-eighth inch between the line 13 of the strip feed press die cut andthe edge of the sheet. That is to say, the dies in the strip feed pressrequire approximately one-eighth inch of material outside the cut forproper functioning. This preparing the strips for the strip lastmentioned material is in addition to the trimming already described sothat the dies ofthe'strip feed press cut in accordance with priorpractice a quarter of an inch from the sheet edge.

In accordance with my present invention I propose to notch thesealternate strips, as indlcated at 17, cuttin back one-eighth inch at acorner, leaving t e part 16 at the end of the longitudinal center of thestrip. Preferably the notch is angled off at 18 into the uncut part ofthe strip. The notching of the sheet m this manner produces trimmed andaccurate feeding edges at an end of each alternate strip and eliminatesthe necessity of trimming the sheet as hereinbefore described, since itis unimportant whether the remaining edge of the unnotched portion ofthe strip be entirely accurate if the bottom of the notch may be engagedby the feeding members of the strip feed press for feeding the strips.

The notch may be conveniently provided by cutting away the materialacross the'ends of intermediate strips, as will be presently more fullydescribed. An accurate reference edge is provided for the stripsintermediate those having the notched edges by cutting on lines 19one-eighth inch away from the die line of cut 13.

The reference numeral 31 indicates the frame of the shear upon which issupported a bed 32 and an arbor 33 in which a cross head 34 is mounted.This cross head carries a male shear die 35 which moves toward and froma female die 36 fixed in the bed 32. The cross head is caused toreciprocate by an eccentric 37 on a shaft 38 in the frame through aneccentric strap 39 connected byan arm 41 with the cross head. The stripsas they are formed fall into receptacles 42 and 43 in the usual manner.

The edge of the strips may be notched conveniently in the shear b maledies 44 arranged on the cross hea at the feeding-in side and co-oerating female dies 45 in the bed 32 of the ear, each pair of said lastmentioned dies cutting between ad acent untrimmed ortions 16 as shown inig. 5.

After t e strips are separated and the ends have been cut to provide theaccurate edge reference portions 17 and 19, they are placed in the stripfeed press shown in Fig. 1. In this figure, reference character 51indicates a pile of strips which are removed singly by suction devices52 for edgewise insertion in a feedway or slot 53 b pushers 54. In thisslot is a strip advancin ar 61 (Fig. 3) which reciprocates with stroesof length equal to the distance between the centers of adjacent linesof out 13. This bar is rovided with feed fingers or members 62 whichengage the reference edge portions 17 and 19 to bring successive enargements of the strips into ac-' curate relation with cuttin andforming dies 63 and 64 of the stri fee ress.

Fi 4 shows the o d met 0d of trimming tin p ate in preparation for thecutting dies. Fig; 5 illustrates the new method of notching a s act oftin plate without first trimming it. Under the new method a sheet of tinplate need not be trimmed along the line 14, and the. broken circularline 13 representing the die out can be moved up to the line 14, andthus the size of the whole sheet of tin plate can be ordered from thetin plate millscorrespondingly smaller. The notches 17 are formed in thepart 15 which was formerly trimmed off.

By my new method of notching sheets of tinplate, smaller size sheets oftinplate are required from the tinplate mills and when the saving oftinplate area on one sheet is multiplied b the thousands of sheets usedin one can ma 'ng factory'alone the importance of the invention becomesat once apparent.

It is thought that the invention and many of its attendant advantageswill be understood from the foregoing description, and it will beapparent that various changes may be made in the form, construction andarrangement of the parts without departing from the spirit and scope ofthe invention, or sacrificing all of its material advantages, the formhereinbefore described being merely a preferred embodiment thereof.

I claim:

1. A method of forming non-rectangular sheet metal articles from 'asheet of material, which comprises, cuttin the sheet into strips fromwhich a number 0 said articles may be cut and formed, and as an incidentto the cutting operation forming notches in an end of the sheet wherebyeach stri is formed with an accurate end edge for su sequent feeding,and then feeding the strip through a stri feed press by engagement withthe said an edge thereof. 4

2. The method of forming non-rectangular sheet metal articles from asheet of material, which comprises, trimming alternate portions from theedge of said sheet preparatory to forming strips with trimmed end edges,cutting said sheet into strips with the alternate untrimmed portionsarranged at an end of each alternate strip but not completely across it,and feeding said strips through a strip feed press by engagement withthe ends of said strips and at the trimmed portions thereof.

3. A method of forming non-rectangular sheet metal articles from a sheetof material, which comprises, cutting the sheet into alternate longerand shorter strips provided with trimmed ends for the shorter strips andparalternate strips through a strip feed press by the engagement of theends of said strips and at the trimmed portions thereof.

5. A method of forming non-rectangular sheet metal articles from a sheetof material, which comprises, trimming portions from an edge of saidsheet to provide trimmed and untrimmed edges for strips to be cut fromsaid sheet, cutting said sheet into strips and feeding said stripsthrough a strip feed press by the engagement of theends of said stripsat the trimmed portions thereof.

JOHN H. MURCH.

